‘Cry' of a
Shredded Star Heralds a New Era for Testing Relativity
Last year,
astronomers discovered a quiescent black hole in a distant galaxy that erupted
after shredding and consuming a passing star. Now researchers have identified a
distinctive X-ray signal observed in the days following the outburst that comes
from matter on the verge of falling into the black hole.
This
tell-tale signal, called a quasi-periodic oscillation or QPO, is a
characteristic feature of the accretion disks that often surround the most
compact objects in the universe -- white dwarf stars, neutron stars and black
holes. QPOs have been seen in many stellar-mass black holes, and there is
tantalizing evidence for them in a few black holes that may have middleweight
masses between 100 and 100,000 times the sun's.
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